Method of making stretchable woven fabric



April 1958 I s. J. TAYLOR 2,831,235

METHOD OF MAKING STRETCHABLE WOVEN FABRIC Filed Dec. 22, 1955 A6- /0 v T a Q U g Q 7/ 3 l corroxv /0 /0 77 v A5 INVENTOR 50w YL ER J. Z4 YA OR ATTORNEY r 2,831,235 Patented Apr. 22, 1958 METHOD or MAKING STRETCHABLE WOVEN FABRIC Schuyler J. Taylor, Portland, Conn., assignor to The Russell Manufacturing Company, Middletown, Conn., a corporation of Connecticut Application December 22, 1955, Serial No. 554,820

4 Claims. (Cl. 28-74) This invention relates to an elastic fabric woven from yarns composed of non-stretchable fibers and particularly to an elastic tape composed of glass fiber yarns.

An object of the invention is to provide an elastic insulating tape suitable for protecting electrical conductors.

Another object is to provide a tape of the above type having sufficient resilience to bind itself securely around vertical conductors or irregular shapes without the use of adhesives.

Another object is to provide a tape of the above type which is resistant to high temperatures.

Another object is to provide a novel and improved fabric having the characteristics above enumerated.

Various other objects and advantages will be apparent as the nature of the invention is more fully disclosed.

In accordance with the present invention the elastic yarn is prepared by winding a thread of thermoplastic synthetic fibers, such as a thread of spun glass fibers herein referred to as fiberglass, around a core composed of a carbonizable yarn, such as Kraftwood or cotton, or other cellulosic materials, so as to form the thermoplastic thread into a helix. The winding may be effected in a rubber covering machine of known type which is in common use for wrapping a rubber strip around a conductor.

This wrapped yarn is then woven into a fabric with or without other threads of the same thermoplastic fibers. The fabric is then treated to temper the helically wound threads so as to set the same in their helical form and to remove the core, leaving a fabric composed of elastic spring-like yarns.

As an example an electrical insulating tape can be made of fiberglass threads wrapped around a cotton core and woven as warp with a straight fiberglass filter thread.

The fabric is then subjected to a tempering and carbonizing temperature of for example 600 F. At this temperature the helical fiberglass thread is tempered and set in helical form and the cotton core is converted to ash which can be readily removed by blowing or washing the fabric.

The fabric can then be coated with a heat-resistant insulation such as a silicone rubber-like composition. Such a coating is stretchable with the tape and provides a body to restrict the stretchability and to cause the tape to conform readily to an irregular surface or to grip a smooth surface such as a straight conductor.

The helical elastic yarn may be used as filler with nonstretchable straight warp or may be used for both filler and warp according to the result desired.

The elastic helical yarn may also be combined with non-stretchable yarn to choke the stretchability to any desired extent.

Specific embodiments are shown in the accompanying drawings in which:

Fig. 1 is a perspective view of a wrapped warp yarn;

Fig. 2 is a broken plan view of a woven tape;

Fig. 3 is a warpwise section taken on the line 3-3 of Fig. 2;

Fig. 4 is a fillerwise section taken on the line 4-4 of Fig. 2;

Fig. 5 is a similar fillerwise section of the final fabric with the warp cores removed and with a coating applied; and i Fig. 6 is a detail view of a fabric having elastic helical yarn for both warp and filler and with non-stretchable yarns disposed warpwise to limit the stretchability.

Referring to the drawing, Fig. 1 shows a yarn 9 composed of a cotton core 10 wrapped with a thread 11 of fiberglass above described.

In Figs. 2 to 4 the fabric is shown as composed of a plurality of yarns 9 as warp interwoven with filler threads 15 of fiberglass which may be formed from two filaments twisted together into a two-ply yarn.

Fig. 5 shows the final product in which the cores 10 have been removed to leave helical spring-like warps composed of the fiberglass coils 11. A coating 16 such as a silicone rubberis disposed on at least one side of the tape. The coating may be applied to both surfaces if desired by dipping the tape into a silicone bath.

The carbonizable core may be replaced by a soluble core if the wrapping threads are of a type which will not withstand carbonizing temperatures, for example nylon, in which case the fabric is subjected to a solubilizing agent and heated to a temperature suited to set the nylon in coil form. v

In Fig. 6 the coiled yarn 11 is woven for both Warp and filler and strands 17 of a non-stretchable material are woven as warp with the coiled yarn 11. The non-stretchable yarn 17 is woven loosely to provide for a predetermined amount of stretch. Crimped yarn having a limited stretch may be used if desired to provide for a limited controlled stretch.

The straight yarns 17 may be used in both warp and filler or may be omitted as desired.

Also the coiled yarn 11 may be wound on a core 10 in a plurality of layers extending in the same or in opposite directions or a plurality of yarns 11 may be wound together as interleaved helices. Such plural windings serve to increase the fabric strength and to conserve the cores which must be later removed.

This fabric is useful where two-way stretch is desired. If fillerwise stretch only is desired the coiled warp yarns 11 are omitted and the yarns 17 used as the warp.

What is claimed is:

l. The method of making a high temperature electrical insulating tape which comprises Wrapping a thread composed of glass fibers around a carbonizable core to form a Wrapped yarn, weaving said yarn with non-stretchable threads composed of glass fibers into a tape, subjecting said tape to a temperature to carbonize said core and to set the wrapping thread in helical form, and removing said carbonized core to leave an elastic spring-like yarn.

2. The method set forth in claim 1 in which said core is composed of cellulosic material.

3. The method set forth in claim 1 in which said core is composed of cotton material.

4. The method of making a high temperature electrical insulating tape which comprises wrapping a thread composed of glass fibers around a carbo-nizable core to form a wrapped yarn, weaving said yarn as warp with filler threads composed of glass fibers into a tape, sub- (References on following page) References Cited in the file of this patent UNITED STATES PATENTS Slayter Oct. 11, 1938 Johnson et a1. Feb. 3, 1948 Foster Oct. 12, 1948 Rand Mar. 10, 1953 Teague May 11, 1954 FOREIGN PATENTS Great Britain Jan. 2, 1945 

4. THE METHOD OF MAKING A HIGH TEMPERATURE ELECTRICAL INSULATING TAPE WHICH COMPRISES WRAPPING A THREAD COMPOSED OF GLASS FIBERS AROUND A CARBONIZABLE CORE TO FORM A WRAPPED YARN, WEAVING SAID YARN AS WARP WITH FILLER THREADS COMPOSED OF GLASS FIBERS INTO A TAPE, SUBJECTING SAID TAPE TO A TEMPERATURE TO CARBONIZE SAID CORE AND TO SET THE WRAPPING THREAD IN HELICAL FORM, REMOVING SAID CARBONIZED CORE TO LEAVE AN ELASTIC SPRING-LIKE WARP, AND APPLYING TO SAID TAPE A COATING OF A SILICONE RUBBER TO IMPROVE THE ELECTRICAL INSULATING PROPERTIES THEREOF AND TO RESTRICT THE STRETCHABILITY OF THE WARP. 